Method and apparatus for communicating via virtual office telephone extensions

ABSTRACT

A system for (and a method of) selectively establishing communication with at least one wireless device associated with a single telephone number serving as a virtual office extension is provided. In a preferred embodiment, the system includes a wireless connect unit in communication with an enterprise private branch exchange (PBX) network. The wireless connect unit preferably serves as a gateway between the PBX and one or more remote communication devices, including at least one wireless device, associated with a virtual extension telephone number. The remote wireless device can be used as a standard PBX office telephone for both inbound and outbound telephone calls. Thus, features of the PBX network (e.g., voice mail, direct extension dialing, corporate calling plan, etc.) are available to the remote wireless device even though it is not physically connected to the PBX. When the system receives an incoming call, it can route the call to a remote wireless device associated with a virtual extension, or to combination of devices simultaneously, or as desired by the user.

This application is a continuation of application Ser. No. 09/879,917,filed Jun. 14, 2001, which claims the benefit of U.S. provisional patentapplication No. 60/211,392, filed Jun. 14, 2000, which are herebyincorporated by reference in their entireties.

BACKGROUND

The office telephone is the primary point of contact of most businesspeople. Typically, corporations invest significantly in their officetelephone infrastructure, including the considerable costs ofconstructing and maintaining a traditional hardwired telephoneinfrastructure at each enterprise location. In addition, corporationstypically invest in a private branch exchange (PBX) network and itsassociated services, including voice mail, paging and unified messagingsystems. Further, most corporations have negotiated contracts with theirtelephone carriers (e.g., local and long distance carriers) to ensurethey obtain the lowest possible rates for calls placed via theircorporate network. However, because the corporate workforce is becomingincreasingly mobile, more business people are using wireless telephonesto conduct their business when they are out of the office. This hasresulted in corporations spending a larger portion of theirtelecommunications budget on wireless communications, with far lessfavorable negotiated rates than the rates of their corporate network. Inaddition, wireless communication systems often lack the enhancedconveniences (e.g., interoffice voice mail, direct extension dialing,etc.) that corporate users have come to expect in the office environmentand for which most of the costs may have already been paid (e.g., thePBX network).

A solution to the aforementioned problems would be to assign toemployees wireless telephony devices (e.g., wireless telephones orpagers) able to access the office telephone system as though they wereconventional desktop telephones hardwired to the company's PBX. It isdesirable to incorporate wireless devices into the PBX network so thatusers may place and receive telephone calls using the office PBXtelephone system whether they are at their desks or at a remote location(e.g., away from their desks, out of the office, etc.). This would allowthe enhanced conveniences of today's PBX networks (e.g., interofficevoice mail, direct extension dialing, etc.) to be available on wirelessdevices—a feature which is needed in today's society.

There have been recent attempts to incorporate wireless telephones intoPBX networks. One system provided by Ericsson, requires the creation ofa mini-cellular network within the confines of the enterprise. Acellular switching unit, unique wireless telephones and an auxiliaryserver are required to route inbound telephone calls to a wirelesshandset serving as a remote office telephone.

An in-building wireless system has been proposed by Nortel Networks.This system requires the wiring of pico-cells throughout theenterprise's building. The system routes inbound telephone calls tospecialized wireless telephones serving as additional office PBXtelephones. The wireless telephones cannot be used as conventionalstandard wireless telephones until they leave the premises.

These systems allow use of a wireless telephone as an office telephone,but they are not without their shortcomings. For example, each systemrequires specialized cellular equipment and wireless handsets. Moreover,the systems only use the wireless telephones for inbound telephonecalls. In addition, these systems cannot use the wireless telephone as aconventional wireless telephone (i.e., not part of the enterprise's PBXnetwork) within the building.

SUMMARY

A system for (and a method of) selectively establishing communicationwith one or more of a plurality of wireless devices serving as a virtualoffice telephone is provided. In a preferred embodiment, the systemincludes a wireless connect unit preferably serving as (or inconjunction with) an enterprise PBX. The wireless devices can be used(on-site or off-site) as standard PBX office telephones for both inboundand outbound telephone calls. Thus, features of the PBX network (e.g.,voice mail, direct extension dialing, corporate calling plan, etc.) maybe made available to the wireless device even though it is notphysically connected to any enterprise telecommunications network (e.g.,PBX). This system of virtual office telephones can be used to providewireless devices the same level of service traditionally provided tohardwired telephones on a standard enterprise PBX network. In accordancewith an embodiment of the invention, when the system receives anincoming call, it can route the call to a wireless device associatedwith a virtual office telephone, as well as to a combination of devicessimultaneously, or as desired by the user. Outgoing calls can be placedfrom a wireless device associated with a virtual office telephone bydialing another extension telephone number (e.g., using the office PBXsystem) or by conventional dialing (e.g., using the PSTN).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary telecommunication system constructed inaccordance with an embodiment of the invention.

FIG. 2. illustrates a wireless connect unit in accordance with anembodiment of the invention.

FIG. 3 illustrates in flowchart form exemplary inboundstation-to-station call processing performed in accordance with anembodiment of the invention.

FIG. 4 illustrates in flowchart form exemplary inbound direct inwarddialing (DID) call processing performed in accordance with an embodimentof the invention.

FIG. 5 illustrates in flowchart form exemplary remote outbound callprocessing performed in accordance with an embodiment of the invention.

FIG. 6 illustrates another exemplary telecommunication systemconstructed in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments and applications of the invention will now bedescribed. Other embodiments may be realized and structural or logicalchanges may be made to the disclosed embodiments without departing fromthe spirit or scope of the invention. Although the preferred embodimentsdisclosed herein have been particularly described as applied to abusiness or office environment, it should be readily apparent that theinvention may be embodied for any use or application having the same orsimilar problems.

The invention is more fully understood with reference to the preferredembodiments depicted in FIGS. 1-6. An exemplary embodiment of theinvention is discussed and illustrated with reference to itsimplementation within an office building or other enterpriseestablishment. In an office, for example, personnel are assigned tooffices (or cubicles) with each office or person having an associatedoffice telephone extension and an office telephone. The office telephoneextensions are typically associated with a PBX, exchange, or other callprocessing infrastructure. The PBX allows each office, or at least eachuser, to be assigned a telephone extension and a direct inward dial(DID) telephone number. As known in the art, a telephone extension istypically a three or four digit telephone number wherestation-to-station (i.e., office-to-office) calls can be placed bydialing the three or four digit extension. This is commonly referred toas direct extension dialing. As also known in the art, a DID telephonenumber allows external calls (i.e., calls initiated outside of theoffice PBX) to be placed directly to the user or office telephone.

In contrast to traditional enterprise communication networks, apreferred embodiment of the invention employs one or more wirelessdevices as virtual office telephones associated with one or more PBXextensions used in lieu of or in conjunction with standard hardwireddesktop telephone sets (e.g., shown as standard telephone sets 89, 90).Referring to FIG. 1, wireless office telephones 82, 84, 86, 88 are notconnected via hardwired lines to enterprise communication systems (e.g.,PBX 14), but instead may be accessed using conventional wirelessequipment through PSTN 16, 54 to a commercial wireless carriersymbolically represented by a wireless switch 58 and an antenna 60.Because the need for hardwired lines is eliminated for these virtualtelephones, the considerable costs of constructing and maintaining atraditional hardwired telephone infrastructure at each enterpriselocation can be saved. For example, estimates of a large U.S.corporation are that traditional handsets or desktop telephones costmore than $100 per month per telephone due to the increasingly highcosts of establishing and maintaining traditional hardwired telephonelines. For a large enterprise with personnel located in multiplegeographic regions, the cost savings from eliminating traditionalhandsets or desktop telephones may be significant.

The invention is not to be limited to any particular environment. Theinvention may be implemented, for example, in a hotel, boarding house,dormitory, apartment, or other commercial or residential establishment,where individuals are assigned to a unique extension or DID telephonenumber. The term “office” as used herein encompasses a singular room orspace within a business or other enterprise, or a hotel room or similarfacility. The term “user” as used herein encompasses office personnel,hotel guests or other individuals associated with a telephone extensionand DID telephone number.

FIG. 1 illustrates an exemplary telecommunication system 10 constructedin accordance with an embodiment of the invention. As will be discussedbelow, the system 10 provides for a full integration of communicationdevices, such as wireless office telephones 82, 84, 86, 88, wired officetelephones 89, 90, and a personal wireless device 70, into an enterprisecommunication network. In doing so, the system 10 can selectivelyestablish communications with one of a plurality of telephony devicesassociated with a particular telephone extension or DID telephonenumber. Moreover, the system 10 will allow communication devices such aswireless office telephones 82, 84, 86, 88 to perform as fully functionalstandard office telephones for both inbound and outbound communications.That is, wireless devices will be able to use features of the officenetwork (e.g., direct extension dialing, corporate dialing plan, etc.)even though the devices are not directly connected to the office PBX oreven within the confines of the office. The system also allows thewireless devices, including wireless office telephones 82, 84, 86, 88and personal wireless device 70, to operate as independent wirelesstelephones capable of conventional interaction with a commercialwireless carrier if so desired. That is, the wireless devices 82, 84,86, 88, 70 may receive calls placed to its (non-office) DID telephonenumber even though the system 10 also routes PBX calls to the wirelessdevices 82, 84, 86, 88, 70.

The system 10, as particularly illustrated herein, includes an officePBX network 11. The PBX network 11 may include a plurality ofcommunication devices associated with PBX extensions at least logicallyconnected by a conventional PBX 14. The PBX 14, which may be anycommercially available one such as a Meridian 1 PBX produced by NortelNetworks, is connected to a calling network such as a public switchedtelephone network (PSTN) 16 by a primary rate interface (PRI) connection20 or other suitable communication line or medium. The PBX extensionscan be associated with wired or wireless telephones or othercommunication devices known in the art. As illustrated in FIG. 1, fourwireless telephones 82, 84, 86, 88, and two standard wired telephones89, 90 are each associated with different PBX extension, and are showncorresponding to six offices or users. For clarity purposes only, sixtelephones 82, 84, 86, 88, 89, and 90 are illustrated in FIG. 1, but itshould be appreciated that any number or combination of telephones orother communication devices can be supported by the system 10. Moreover,although it is desirable to use wireless telephones in lieu of (or inconjunction with) standard hardwired desktop telephones, the inventionis not to be limited to the particular type of device used in the system10.

The PBX 14 is coupled to a wireless connect unit (WC) 30. The WC 30 isconnected to the PBX 14 in this embodiment by a PRI connection 22 orother suitable communication medium. The WC 30 is also connected to aPSTN 54 by a PRI connection or other suitable digital communicationmedium. The illustrated PRI connection between the WC 30 and the PSTN 54includes a first PRI connection 32, a channel service unit (CSU) 34, anda second PRI connection 36. As known in the art, a CSU is a mechanismfor connecting a computer (or other device) to a digital medium thatallows a customer to utilize their own equipment to retime andregenerate incoming signals. It should be appreciated that theillustrated connection between the WC 30 and the PSTN 54 is one of manysuitable connections. Accordingly, the invention should not be limitedto the illustrated connection. The WC 30 is one of the mechanisms thatallows the integration of virtual office telephones into the PBX network11 and its operation will be described below in more detail.

The WC 30 is preferably connected to a local area network (LAN) 40 by anappropriate communication medium 38. Although a LAN 40 is illustrated,it should be appreciated that any other network could be used. Aplurality of computers (e.g., 42 a, 42 b) may be respectively connectedto the LAN 40 by any appropriate communication lines 44 a, 44 b. Thecomputers 42 a, 42 b can be used by network administrators or others tomaintain WC 30 and other portions of the system 10. The LAN 40 may alsobe connected to the Internet 50 by a suitable communication medium 48. Afirewall 46 may be used for security purposes. In a preferredembodiment, Internet 50 can be used to allow a remote administrationdevice 52 (e.g., a personal computer) to perform remote administrationof WC 30 by office personnel or other authorized users of the system 10.Remote administration will allow office personnel to set userpreferences for particular telephone extensions. Thus, each telephoneextension, particularly those associated with a virtual officetelephone, is individually configurable.

PSTN 54 is connected in this embodiment to a commercial wireless carrierby the wireless switch 58 or other wireless carrier equipment by anappropriate communication medium 56. The wireless switch 58 is connectedto at least one antenna 60 (by an appropriate communication medium 62)for transmitting signals 64 to wireless devices, such as wireless officetelephones 82, 84, 86, 88 or personal wireless device 70. The wirelessdevice could also be a pager, personal digital assistant (PDA), landlinetelephone, facsimile machine or other wired/wireless communicationdevice. It may desirable for the wireless device to be capable ofhandling both (or either) digital and analog communication signals. Itshould be noted that any type of wireless communication protocol (or acombination of different protocols), such as TDMA, CDMA, GSM, AMPS, MSR,iDEN, WAP, etc., could be used.

It should be appreciated that the WC 30 is connected to a wirelesscarrier through a PSTN 54 and not by unique hardware or an in-officecellular network. As a result, WC 30 only has to interface withconventional components, such as the PBX 14 and PSTN 54. Thus, thesystem is substantially technology independent. Moreover, specialwireless devices are not required, which allows the wireless devices tofunction in a conventional manner (e.g., as independent wirelesstelephones) and as part of the PBX network 11 (if so desired) as if theywere hardwired office telephones.

As noted above, the WC 30 allows for the full integration of wirelessdevices into the PBX network 11 in lieu of (or in conjunction with)standard hardwired telephones. In a preferred embodiment, WC 30 is aprocessor-based stand-alone unit capable of handling communicationsdirected to the PBX network 11. In a preferred embodiment, WC 30 iscomposed of one or more processors generically represented by processormodule 310 executing one or more computer programs stored in one or morememory units generically represented by memory module 320, which iscoupled to processor module 310 via bus 330, as shown in FIG. 2. Memorymodule 320 also contains one or more databases and other processingmemory used during the overall operation of system 10, as will bedescribed below. Receiving and transmitting modules 340, 350,respectively, which are coupled to processor module 310 and memorymodule 320 via bus 330, are employed to receive and transmit informationto the PBX and PSTN during call processing, as well as receiving andtransmitting other information such as administrative information.

The modules (310, 320, 330, 340, 350) making up WC 30 may be implementedusing any known hardware or software devices. For example, in oneembodiment, workload performed by receiving and transmitting modules340, 350, as well as some of the processing functions of processormodule 310 of WC 30 are implemented using one or more conventionalprocessor-based programmable telephony interface circuit cards used tointerface WC 30 with PBX 14 and the PSTN. They are programmed to performthe conventional telephony services required to place and receive calls,as well as programmed to perform the unique call processing functionsdescribed below. The WC 30 preferably contains a database of extensionnumbers (also referred to herein as PBX extensions) and DID telephonenumbers associated with each existing PBX extension. The database willbe stored on a computer readable storage medium, which may be part of(e.g., in memory module 320) or connected to the WC 30. The database mayalso contain a wireless connect/PBX extension (hereinafter referred toas a “WC-PBX extension”) and one or more wireless device telephonenumbers associated with each PBX extension. In this embodiment, softwarerunning on the telephony cards interfaces with the database to performthe various call processing functions discussed below.

In this embodiment, the PBX 14 contains a coordinated dialing plan (CDP)steering table. The CDP steering table will be stored and retrieved froma computer readable storage medium, which may be part of or connected tothe PBX 14. The CDP steering table directs the routing of PBX extensionsto the WC 30 over the PRI 22 between the WC 30 and the PBX 14. Inaddition, the CDP steering table of the PBX 14 directs the routing ofWC-PBX extensions received from the WC 30 to the appropriate officeextensions and associated office (or virtual office) telephones.

In accordance with a preferred embodiment of the invention, processormodule 310 executes one or more programs stored in memory module 320 toprocess calls received through PBX 14 or PSTN. FIGS. 3-5 illustrate someof the basic call processing events which WC 30 may be programmed tohandle in accordance with exemplary embodiments of the invention. Asillustrated in FIG. 3, when an incoming station-to-station call (i.e., adirect extension call from one PBX telephone device to another PBXdevice) is received by the PBX 14 for an existing PBX extension (step102), the PBX 14 looks up the PBX extension in the CDP steering table(step 104) to determine where the call should be routed. Based on theCDP steering table the call to the PBX extension is routed to the WC 30(step 106).

As is known in the art, the incoming call will have automatic numberidentification (ANI) and dialed number identification service (DNIS)information. The ANI identifies the telephone number of the callingparty and is traditionally used for “caller ID.” DNIS identifies thetelephone number of the called party. The WC 30 reads the ANI/DNISinformation from the incoming call to obtain the DNIS information (step108). As noted above, the WC 30 has assigned a new WC-PBX extension toeach existing PBX extension. The WC-PBX extension, routing information,and user preferences are obtained by using the DNIS information(identifying the PBX extension) as an index into the WC 30 database(step 110). Routing information will include any additional remotetelephone numbers, voice mail box numbers, or other identificationnumbers of communication devices associated with the PBX extension.

At step 112, the WC 30 out-pulses the WC-PBX extension obtained in step110 for any associated hardwired office telephone (e.g., 89, 90, etc.).Where the associated office telephone is a virtual office telephone(e.g., telephone 82), however, the call is routed through the PSTN 16,54 and the commercial wireless carrier network servicing the associatedwireless device. In response, the commercial wireless carrier relays itssignal through its network (e.g., through the antenna 60) in aconventional manner in an attempt to reach the user or wirelesstelephone associated with the PBX extension dialed. In accordance with apreferred embodiment, at the same time (if desired), the WC 30 attemptsto contact one or more alternative communication devices (e.g.,out-dialing a remote telephone number via the PRI connection between theWC 30 and the PSTN 54). In such an embodiment, the station-to-stationcall is thus routed to both the virtual office telephone and also to atleast one remote device simultaneously or substantially simultaneously(or as determined by the user preferences). It should be noted that theillustrated processing 100 is just one example of how an incomingstation-to-station call may be handled. Individual user preferences mayalter the way the call is processed. It should be noted that in apreferred embodiment, the WC 30 is out-pulsing the WC-PBX extension (forhardwired telephones), dialing the virtual office telephone number, andcontacting one or more remote communication devices. This gives the WC30 control over the connections to the office telephones and any remotedevices.

At step 114, it is determined if the current ring count (i.e., number ofrings) exceeds the maximum ring count defined by the user. Since the WC30 is controlling the call at this time it can track the number ofrings. If the ring count exceeds the maximum ring count, then the WC 30(if desired) forwards the call to the enterprise's voice mail (step120). If the ring count does not exceed the maximum ring count, the WC30 determines if the call is answered at the (virtual or standard)office telephone associated with the PBX extension dialed (step 116).The PBX 14 will issue an off-hook message to the WC 30 if theappropriate standard office telephone is answered. If it is determinedthat the call is answered at the (virtual or standard) office telephone,the WC 30 drops the call's path to any other remote devices (e.g.,personal wireless device 70) via the PSTN 54 and maintains the path tothe office telephone (step 122).

In a preferred embodiment, it may be desired that the call to thevirtual office telephone or any remote devices be actually answered by auser and not by a service in conjunction with the user's wirelesscarrier. In known systems, wireless carriers often answer a call ifthere is a bad connection, the wireless channels are overloaded, or forother reasons (such as initiating a wireless carrier's answeringservice). When the wireless carrier answers the call in thesesituations, the call would appear to WC 30 as an “answered call” even ifthe user did not actually answer the call.

One way to distinguish a user answered call from a wireless serviceanswered call is to prompt the user to transmit an acknowledgementsignal such as a dual tone multi-frequency (DTMF) tone to the WC 30 viathe keypad of the wireless device. Upon detecting the answered call, WC30 can send a voice message instructing the user to “press the # buttonto complete the call.” If the DTMF tone is not received, then the WC 30presumes that the call was answered by the wireless carrier, or that theuser does not want to answer the call which the WC 30 treats as anunanswered call. If at step 118, for example, it is determined that theremote device (e.g., personal wireless device 70) was answered by theuser, the WC 30 drops the WC-PBX extension path and initiates theconnection between the calling party and the remote device (step 124).If the call is not answered at the remote device in step 118, processflow returns to step 114 to check whether the ring count has exceededthe maximum ring count.

In accordance with a preferred embodiment of the invention, the databaseof WC 30 may also contain numerous system-defined user access rights anduser modifiable preferences, which can alter the call processing of theinvention. An office administrator may use the network computers 42 a,42 b or a remote administration device 52 to set user access rights andpriorities (example discussed below with respect to outbound callprocessing 300 illustrated in FIG. 5). The user may use the remoteadministration device 52 to set numerous user preferences. It isdesirable that a Web-based or graphical user interface be used so thatthe user can easily access and set user preferences. The networkcomputers 42 a, 42 b (or remote device 52) may also be used by the userif so desired.

User preferences may include how the user associated with a particularPBX extension wants incoming calls to be routed. For example, the usercan request that incoming calls be routed to the (virtual or standard)office telephone and one or more remote devices simultaneously. The userinstead can request that an incoming call be routed to the officetelephone first, then after a user-defined number of rings, the remotedevice(s) and eventually sent to the PBX voice mail. Alternatively, theuser can request that an incoming call be routed to one or more remotedevices first, then the office telephone, and subsequently to the PBXvoice mail. The user can request that all incoming calls be routeddirectly to the PBX voice mail. The user can request that a menu ofoptions be played to the caller so that the caller can decide how tocomplete the call. The user can set separate ring counts for the officetelephone and remote devices. The user can set dial tone options, whichallows the user to control how long a dial tone is played before a dialtone time-out occurs. The user can adjust the time between dials. Theseare just a few of the user preferences that can be stored and used bythe WC 30, which can alter incoming and out going call processing. Ifthe user does not change the user preferences, or only changes a fewpreferences, system defaults are used.

When receiving an inbound DID call, call processing flow 200 (asillustrated in FIG. 4) is performed in accordance with an embodiment ofthe invention. At step 202, a DID telephone call is dialed by anexternal telephone device and received by system 10 through the PSTN. Ina preferred embodiment, the PSTN has been programmed in advance to routeall DID telephone numbers used by the system 10 to the WC 30. Inaddition, the PSTN has also been programmed to route calls incoming tothe DID telephone number directly to the PBX 14 if the path to the WC 30has failed. That is, the embodiment incorporates a failure path into thesystem 10 to ensure that a failure of the WC 30 or the PRI connectionbetween the WC 30 and the PSTN does not interrupt the operation of theoffice PBX network 11. This is possible since the steering table of theoffice PBX 14 contains the DID telephone numbers. The PBX 14 has thecapability to resolve these DID numbers. Thus, the PBX 14 can be used ifneeded to handle DID telephone calls. For purposes of this discussion,it is presumed that the WC 30 and the connection between the WC 30 andthe PSTN 54 are fully operational. Thus, at step 204, the PSTN routesthe DID call to the WC 30.

The WC 30 reads the ANI/DNIS information from the incoming DID call toobtain the DNIS information (step 206). The WC 30 resolves the call bydetermining what WC-PBX extension is associated with the telephonenumber identified by the DNIS. The WC-PBX extension, routing informationand user preferences are obtained by the WC 30 (step 208). At step 210,the WC 30 out-pulses the PBX 14 through the PRI connection 22 betweenthe WC 30 and PBX 14 with the obtained WC-PBX extension for anyhardwired office telephones (e.g., 89, 90). For any virtual officetelephones associated with the WC-PBX extension, WC 30 out dials thecommercial wireless carrier servicing the associated virtual officetelephone in the same manner described above. In accordance with anembodiment of the invention, at the same time (if desired), the WC 30attempts to contact one or more remote devices (e.g., by out-dialing oneor more user designated remote telephone numbers via the PRI connectionsbetween the WC 30 and the PSTN 54). Therefore, the inbound DID telephonecall may be routed to the (virtual or standard) office telephone and oneor more remote devices (e.g., personal wireless device 70)simultaneously (or as determined by the user preferences). It should benoted that the illustrated processing 200 is just one example of how anincoming DID call may be handled.

At step 212, it is determined whether the current ring count exceeds themaximum ring count defined by the user. If the ring count exceeds themaximum ring count, then the WC 30 forwards the call to the enterprise'svoice mail (step 218). If the ring count does not exceed the maximumring count, the WC 30 determines whether the call is answered at the PBXextension (step 214). If it is determined that the call is answered atthe PBX extension, the WC 30 drops the call's path to the remote devicevia the PSTN and maintains the path to the PBX extension (i.e., virtualor standard office telephone) (step 220). If at step 214 it isdetermined that the call is not answered at the PBX extension, the WC 30determines if the call is answered at the remote device (e.g., 70) (step216). In a preferred embodiment, it may be desired that calls to virtualoffice telephones 82, 84, 86, 88 or remote devices are actually answeredby the user and not by a service of the wireless carrier. Therefore, todistinguish a user answered call from a wireless service answered call,the WC 30 may require an acknowledgment signal as in the previousembodiment described above. If at step 216 it is determined that thecall was answered by the user using a remote device, the WC 30 drops thepath to the PBX extension and maintains the connection to the answeringremote device (step 222). (As an alternative, control and responsibilityfor the remainder of the call can be left with the PSTN in order to freeup PRI channels between WC 30 and PSTN 54.) If the call is not answeredby any remote device in step 216, process returns to step 212 to checkwhether the ring count has exceeded the maximum ring count.

Initially, the call processing reduces the processing load on the PBX14, since the WC 30 (and not PBX 14) is resolving the DID telephonenumbers. This allows the PBX 14 to handle call processing for moreextensions if desired. Additionally, since the WC 30 is resolving theDID calls, the WC 30 can out pulse the PBX 14 and out dial the PSTN 54simultaneously (if desired) without waiting for the PBX 14 toprocess/resolve the call. Moreover, as noted above, redundancy isprovided by allowing the PBX network 11 to function as a standard PBX ifthe WC 30 or the link between the WC 30 and the PSTN 54 fails.

In accordance with a preferred embodiment, WC 30 allows virtual officetelephones (e.g., wireless telephones 82, 84, 86, 88) or any remotedevice (e.g., remote device 70) to act as standard office PBX telephonesfor outbound telephone calls following call processing flow 300illustrated in FIG. 5. That is, a user will be able to use his virtualoffice telephone (or any remote device) to make station-to-station callsas if he were using a hardwired standard office telephone directlyconnected to the office PBX 14. From the virtual office telephone orremote device, the user will also be able to perform other PBX functionsas well. At step 302, a user places a call to the WC 30 from the device82, 84, 86, 88, 70. One way the user may do this would be to define aspeed dial key (or sequence of keys) on the device handset. When theuser activates the appropriate speed dial key/keys, the device 82, 84,86, 88, 70 dials into the WC 30. Another way to dial into the WC 30would be by fixed dialing. Fixed dialing is a feature provided by thewireless carrier to always connect the wireless telephone to aparticular number or service, and, in this case, it would connect theuser to the WC 30. Any number of other methods may be used to dial intothe WC 30.

At step 304, the WC 30 reads the ANI/DNIS information received from thedevice 82, 84, 86, 88, 70 to obtain the ANI information. The ANIidentifies the telephone number of the calling device. The WC 30 usesthe ANI information to obtain the user's access rights and userpreferences (step 306). As noted above, a user is provided with theability to set various user preferences. The enterprise also has theability to set access rights defining what type of calls the user canplace from the remote device (e.g., local, long distance, international,station-to-station, etc.). For example, if using PRI connections betweenthe PSTN 54 and the WC 30, the PBX 14 and the WC 30, and the PBX 14 andthe PSTN 16, users can be assigned into particular access groups byassigning each user to a particular channel or group of channels of thePRI. The user assignments can be stored in a database memory withinmemory module 320 of WC 30 for access during a validation orauthentication process performed by processor module 310. In thealternative, the responsibility over the user assignments can beincorporated into PBX 14 or some other (on-site/remote) equipment.

As is known in the art, in North America and Japan, for example, eachPRI contains 23 “B” channels that can be used for voice communications.Each B channel can be programmed with different calling capabilities bythe PBX 14. That is, some channels can be programmed for all types ofcalls (e.g., international, long distance, local etc.), others for longdistance and local calls, while others can be programmed solely forlocal or internal station-to-station calls. The channels can also berestricted to a limited number of authorized telephone numbers as well.The programming can be determined by the enterprise. Since the channelscan be programmed with different calling capabilities, the enterprisecan implement different access groups, with each group defining a user'sdevice access.

This feature significantly limits the enterprise's device (e.g.,wireless service) costs because user access to services can besubstantially restricted. For example, the enterprise may want deliverypersonnel to have a wireless telephone for internal dialing purposes,but may be afraid of misuse by the personnel. Implementing the aboveembodiment, the enterprise can group all wireless telephones assigned toits delivery personnel to a channel(s) restricted solely to internalcalls. Any grouping is possible. Priorities may also be assigned. A userassigned to group 1 (programmed for all calling capabilities) may begiven priority to bump a user assigned to group 2 (having less callingcapabilities) in the event that the channels assigned to group 1 arebusy. Any grouping or priority scheme can be implemented by theenterprise and is application specific.

At step 308, the WC 30 “spoofs” a dial tone to the virtual officetelephone 82, 84, 86, 88 and remote device 70. That is, the WC 30generates and transmits a dial tone as if the user had picked up aconventional office telephone hardwired to the PBX 14. In a preferredembodiment, the spoofing of the dial tone is achieved by the WCinternally generating the appropriate tone (e.g., through software orhardware modules). The dial tone is then played to the virtual officetelephone 82, 84, 86, 88 or remote device 70 as a prompt while waitingto receive DTMF digits from the user indicating the telephone number theuser wishes to dial. At this point in the call process flow 300, theuser is connected to the office PBX and may access any of its standardfeatures. For purposes of this illustrated embodiment, it is presumedthat the user wishes to place an outbound call at this time. At step310, the user attempts to place a call and the WC 30 receives the numberdialed by the user. At step 312, the WC 30 determines if the user isauthorized to make the call. For example, the WC 30 checks the user'saccess rights, and if the user is authorized to place the call, the callis routed to the correct channel by the WC 30 based on user preferences,access rights and the channel definitions (step 314). If the user is notauthorized to place the call (i.e., the call exceeds the user's accessrights), the WC 30 performs unauthorized call processing (step 316).Unauthorized call processing may include playing a message to the userstating that the user does not have authority to place the call,disconnecting the call, or any other action desired by the enterprise.

If the user decides to place a station-to-station call, for example, thecall would appear to be an internally dialed call at the destinationoffice telephone. For example, if the PBX 14 uses a different ring forinternal calls, then the internal ring would be sent to the destinationtelephone even if the call was made from a virtual office telephone 82,84, 86, 88 or remote device 70. If the PBX 14 normally displays the PBXextension of the calling party on the called office phone, then the PBXextension of the calling party would be displayed on the called officetelephone even though the call was initiated from a virtual officetelephone 82, 84, 86, 88 or remote device 70.

Many enterprises have already provided wireless communication devices totheir personnel. These wireless devices already have existing telephonenumbers and are external to the enterprise PBX. Since the devices arealready in use by personnel and their clients, the enterprise may notwant to change their telephone numbers. There is a need to integratethese telephone numbers into the enterprise PBX. One way to integratethese telephone numbers would be to forward their unanswered calls tothe PBX voice mail. This can be accomplished in accordance with anembodiment of the invention whether the wireless device is associatedwith a PBX extension or not.

For example, the enterprise can purchase additional DID telephonenumbers from the telephone company (if necessary). These additional DIDtelephone numbers are stored in the database of the WC 30 together withspecial routing instructions to route all calls directly to a user's PBXvoice mail box (or other destination as desired). The user of a wirelesstelephone can program the wireless telephone to forward unanswered callsto his associated DID telephone number. Alternatively, the user can havethe wireless carrier forward unanswered calls to the DID telephonenumber as well. This way, any unanswered call to the wireless telephonewill be forwarded to the WC 30, which resolves the DID and forwards thecall to the appropriate PBX voice mail box. Using this feature, thelikelihood is increased that the user will retrieve his messages sincehe can retrieve all of his messages through the PBX voice mail. Thisalso alleviates the need for the user to have a separate voice mailservice from the wireless carrier, which may reduce the cost of thewireless service.

The invention can be embodied in any number of different applications.One embodiment, for example, applies the invention to a hotel having alarge number of rooms without routing telephone lines or other wiring toeach room. Many if not all rooms would have a telephone extension thatis associated with the enterprise PBX, as well as a wireless telephoneassociated with the PBX extension (integrated using an embodiment of theinvention). In addition, one or more rooms could employ more than onePBX extension if desired by hotel guests. If, for example, a guest ofthe hotel were using a standard room telephone and associated PBXextension for network access by his personal computer, he could stillmake and receive calls through a virtual room telephone using a wirelesstelephone or other device in a manner transparent to the calling party.This embodiment allows an enterprise to multiply the number of itstelephone lines without incurring the expense of conventional wiringpreviously required to install additional lines for the hotel rooms.

In a preferred embodiment, WC 30 is co-located with the enterprises' PBX14, but may also be centrally located in a remote location ordistributed among the many locations, or any combination of thesearrangements.

While the preferred embodiments have been described thus far withreference to a PBX network 11 and hardwired standard office telephones,this structure is not required and a system of virtual office telephonesmay be implemented using only the wireless connect WC 30, as shown inFIG. 6. In this embodiment, the system 10′ of virtual office telephonescould provide a central location for receiving calls to an enterpriseand placing calls from an enterprise, while affording system users theflexibility of wireless office telephones. Referring to FIG. 6, allfeatures of the exemplary telecommunication system 10 illustrated inFIG. 1 are included with the exception of PBX network 11 includingconventional PBX 14, PRIs 20, 22 and PSTN 16. Instead, the WC 30 directsall calls to and from the wireless office telephones to the PSTN 54through the CSU 34 and PRIs 32, 36 for routing to wireless officedevices 82, 84, 86, 88 or personal wireless device 70 using conventionalwireless equipment as described with reference to FIG. 1. Although thetraditional features of a conventional PBX, such as PBX voice mail, useraccess rights, multiple-location routing and channel definitions, havebeen removed in this embodiment, many of these features may be availablefrom WC 30 or the wireless carrier for the wireless devices 82, 84, 86,88, 70. Compared to the cost of a traditional PBX system, for smallerenterprises, obtaining these features from the wireless carrier may be amore cost effective option.

While preferred embodiments have been specifically described andillustrated herein, it should be apparent that many modifications to theembodiments and implementations of the invention can be made withoutdeparting from the spirit or scope of the invention. For example, whilethe preferred embodiments illustrated herein have been limited to theprocessing of voice (packet or circuit switched) calls, it should bereadily apparent that any form of call (e.g., audio, video, data) may beprocessed through WC 30 to any communication device (e.g., cellularphone, pager, office/residential landline telephone, computer terminal,personal digital assistant (PDA), etc.). The individual method steps ofthe exemplary operational flows illustrated in FIGS. 3-5 may beinterchanged in order, combined, replaced or even added to withoutdeparting from the scope of the invention. Any number of differentoperations not illustrated herein may be performed utilizing theinvention.

In addition, while the illustrated embodiments have demonstratedimplementations of the invention using PBX-based communication systems,it should be readily apparent that the WC module may be connected(directly or indirectly) with any other network switching device orcommunication system used to process calls such as a central switchingoffice, Centrex system, or Internet server for telephone calls made overthe public switched telephone network, private telephone networks, oreven Internet Protocol (IP) telephony networks made over the Internet.

It should be apparent that, while only PRI lines (e.g., between PBX 14and WC 30, between PBX 14 and PSTN 16) have been illustrated indiscussing preferred embodiments of the invention, these communicationlines (as well as any other communication lines or media discussedherein) may be of any form, format, or medium (e.g., PRI, T1, OC3,electrical, optical, wired, wireless, digital, analog, etc.). Moreover,although PSTN 16, 54 are depicted as separate networks for illustrationpurposes, it should be readily apparent that a single PSTN network alonemay be used in reducing the invention to practice. The use of acommercial wireless carrier network (represented by the wireless switch58 and the antenna 60) as described herein may be implemented using oneor more commercial carriers using the same or different signalingprotocols (e.g., Sprint PCS and Nextel, etc.) depending on thecommunication devices registered with the system.

The modules described herein such as the modules making up WC 30, aswell as WC 30 and PBX 14 themselves, may be one or more hardware,software, or hybrid components residing in (or distributed among) one ormore local or remote systems. It should be readily apparent that themodules may be combined (e.g., WC 30 and PBX 14) or further separatedinto a variety of different components, sharing different resources(including processing units, memory, clock devices, software routines,etc.) as required for the particular implementation of the embodimentsdisclosed herein. Indeed, even a single general purpose computerexecuting a computer program stored on a recording medium to produce thefunctionality and any other memory devices referred to herein may beutilized to implement the illustrated embodiments. User interfacedevices utilized by in or in conjunction with WC 30 may be any deviceused to input and/or output information. The interface devices may beimplemented as a graphical user interface (GUI) containing a display orthe like, or may be a link to other user input/output devices known inthe art.

Furthermore, memory units employed by the system may be any one or moreof the known storage devices (e.g., Random Access Memory (RAM), ReadOnly Memory (ROM), hard disk drive (HDD), floppy drive, zip drive,compact disk-ROM, DVD, bubble memory, etc.), and may also be one or morememory devices embedded within a CPU, or shared with one or more of theother components. Accordingly, the invention is not to be seen aslimited by the foregoing description, but is only limited by the scopeof the appended claims.

1. A method of providing access to an enterprise telecommunicationnetwork to a wireless telephone for an outgoing telephone call, saidmethod comprises: receiving a first telephone call from the wirelesstelephone; identifying a wireless telephone number of the wirelesstelephone; using the wireless telephone number to retrieve an enterprisetelephone extension associated with the enterprise telecommunicationnetwork; retrieving at least one user preference and at least oneenterprise preference associated with the retrieved enterprise telephoneextension; generating a simulated dial tone; sending the simulated dialtone to the wireless telephone in response to the first telephone callfrom the wireless telephone to indicate the wireless telephone'sconnection to the enterprise telecommunication network; and providingthe wireless telephone with telecommunication access to the enterprisetelecommunication network for an second telephone call based on theretrieved at least one user preference and the retrieved at least oneenterprise preference.
 2. The method of claim 1, wherein the at leastone enterprise preference comprises an access group defining authorizedoutbound call access rights for a user of the wireless telephone.
 3. Themethod of claim 1, further comprising the act of allowing the wirelesstelephone to place a call using the services of the enterprisetelecommunication network to another extension of the enterprisetelecommunication network.
 4. The method of claim 1, wherein said atleast one user preference comprises a dial tone timeout period, whereina user of the wireless telephone is prevented from placing a callthrough the enterprise network after the dial tone timeout periodexpires.
 5. The method of claim 1, further comprising the act ofallowing the wireless telephone to place a call using the services ofthe enterprise telecommunication network to a telephony device notassociated with the enterprise telecommunication network.
 6. Atelecommunication device comprising: a storage medium for storing atleast one user preference and at least one enterprise preferenceassociated with each extension of an enterprise telecommunicationnetwork; and a telephony interface coupled to the storage medium and theenterprise telecommunication network, said telephony interface beingadapted to: receive a first telephone call from a wireless telephone,identify a wireless telephone number of the wireless telephone, use thewireless telephone number to retrieve a first enterprise extensiontelephone number associated with an extension of the enterprisetelecommunication network and with the wireless telephone, retrieve theat least one user preference and enterprise preference associated withthe retrieved first enterprise extension telephone number from thestorage medium, determine whether the wireless telephone can be providedaccess to services of the enterprise telecommunication network, and ifit is determined that the wireless telephone can be provided access toservices of the enterprise telecommunication network, the interface isfurther adapted to generate and send a simulated dial tone to thewireless telephone in response to the first telephone call from thewireless telephone to indicate the wireless telephone's connection tothe enterprise telecommunication network to and thereby alert thewireless telephone that access to the enterprise telecommunicationnetwork has been granted for a second telephone call.
 7. The device ofclaim 6, wherein if it is determined that the wireless telephone cannotbe provided access to the services of the enterprise telecommunicationnetwork, the interface is further adapted to perform unauthorized callprocessing.
 8. The device of claim 6, wherein if it is determined thatthe wireless telephone cannot be provided access to the services of theenterprise telecommunication network, the interface is further adaptedto play a message to the wireless telephone indicating that the wirelesstelephone cannot be provided access to the services of the enterprisetelecommunication network.
 9. The device of claim 6, wherein if it isdetermined that the wireless telephone cannot be provided access toservices of the enterprise telecommunication network, the interface isfurther adapted to disconnect the call from the wireless telephone. 10.The device of claim 6, wherein said at least one enterprise preferencecomprises an access group defining authorized outbound call access of auser of the wireless telephone.
 11. The device of claim 6, wherein theinterface is further adapted to allow the wireless telephone to place acall using the services of the enterprise telecommunication network toanother extension of the enterprise telecommunication network.
 12. Thedevice of claim 6, wherein the interface is further adapted to allow thewireless telephone to place a call using the services of the enterprisetelecommunication network to a telephony device not associated with theenterprise telecommunication network.